A copying operation is necessary in a large volume object transmission operation of, for example, a hosting service to improve reliability and access response. For example, a client terminal or an object server which receives a write request from the client terminal transmits the write request to other multiple object servers in parallel.
FIG. 25 is an outline drawing showing a device constitution of a distributed object system 700.
The distributed object system 700 is a system in which objects transmitted from a client terminal 710 is copied by object servers 720a-720c. 
In the distributed object system 700, a network band is shared by the object servers 720a-720c, and therefore, the network band can be a bottleneck with regard to a speed of writing the objects into object databases by the object servers 720a-720c. 
FIG. 26 is an outline drawing showing other device constitution including a distributed object system 800.
In the distributed object system 800 shown in FIG. 26, object servers 810a-810c are constituted so as to sequentially transmit/relay an object, and a pipelining operation is applied to each of object servers 810a-810c in that a parallel operation is conducted including a reading operation of an object transmitted via a network, a writing operation of the object into a database and a transmission operation to the following object server. In such a manner, the distributed object system 800 shares a network band between multiple object servers and prevents the formation of a bottleneck.
FIG. 27 is an outline drawing showing a device constitution of a distributed object system 900 other than the above.
As a technique of the art, Dolly+ shown in FIG. 27 is introduced. In a pipelining operation of Dolly+ in which an object is copied between multiple object servers, FIG. 27 shows an operation and constitution in that an object server which has a problem is removed from targets of the copying operation.